Clutch device of sprag type



Nov. 9, 1965 E. J. RYAN CLUTCH DEVICE OF SPRAG TYPE 2 Sheets-Sheet 1 Filed Oct. 1. 1963 INVENTOR. :EEWtL-mi QLE 1111 BY l xiv? j Z. uil 1%,

NOV. 9, E. J. RYAN CLUTCH DEVICE 0F SPRAG TYPE Filed Oct. 1, 1963 2 Sheets-Sheet 2 :E'ijllp 1N VENTOR.

Eniwurfi. lRytm maamujb United States Patent 3,216,544 CLUTCH DEVICE 0F SPRAG TYPE Edward J. Ryan, Colonie, N.Y., assignor to the United States of America as represented by the Secretary of the Army Filed Oct. 1, 1963, Ser. No. 313,133 3 Claims. (Cl. 19245.1)

(Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to clutches and pertains more particularly to clutches of the sprag type.

It is the object of this invention to provide a clutch whereby'one of two rotary members is free to move relative to the other in both directions and the second member is free to move respective to the first member in one direction but, when rotated in the opposite direction, is engaged with the first member for transfer of torque thereto.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

FIG. 1 is a view of the rear end of a cannon partially sectioned to clearly disclose the structure of the breechblock actuating crank;

FIG. 2 is a view taken along line 22 of FIG. 1;

FIG. 3 is a view taken along line 3-3 of FIG. 2;

FIG. 4 is an enlarged view taken along line 44 of FIG. 3 showing the relationship of the parts of the cltuch when the breech is closed;

FIG. 5 is a view similar to FIG. 4 but showing the relationship of the clutch parts during manual opening of the breech;

FIG. 6 is a similar view but showing the relationship of the clutch parts when the breechblock is driven to the closed position;

FIG. 7 is a similar view but showing the relationship of the clutch parts when the beechblock opening spring is energized during recoil of the cannon; and

FIG. 8 is a similar view but showing the relationship of the clutch parts when the breechblock is driven closed.

Shown in the figures is a cannon 12 which is conventionally mounted on a mount 13 for translational displacement in recoil and counterrecoil strokes. Cannon 12 includes a breech ring 14 and a breechblock 16 which are slidingly mounted therein for vertical displacement between an upper breech closed position and a lower breech open position. Breechblock 16 is releasably latched in the breech open position by conventional extractor means (not shown) which are arranged to be tripped to release the breechblock by a round when inserted through breech ring 14 into the cannons firing tube.

Breechblock 16 is vertically displaced by an actuating mechanism, which includes a tubular shaft 20 journaled in breech ring 14, and a crank 22, which is integral with such shaft and which is cammingly engaged with breachblock 16, as shown in FIG. 2, so that rotation of the crank is converted to translational displacement of the breechblock. Referring to FIG. 2, rotation of crank 22 in a clockwise direction raises breechblock 16 and rotation of the crank in a counterclockwise position lowers the breechblock. A coil-type torsion spring 24 is coiled around shaft 20 and is operationally disposed between breech ring 14 and breechblock 16 so as to be energized when the breechblock is lowered to the breech open position so as to utilize the stored energy in raising the breechblock to the breech closed position.

3,215,544 Patented Nov. 9, 1965 Housed inside shaft 29 is a drive mechanism which includes a torque tube 28 journaled in the shaft and a multi-leaf torsion spring 30 housed within the torque tube. Spring 30 drives breechblock 16 to the breach open position and is designed to store sutlicient energy to overpower spring 24, which drives the breechblock to the closed position, so that such spring 24 is wound up by spring 30 when the breechblock is lowered. One end of spring 30 is anchored to breech ring 14 by means of a collar 32 while the opposite end is fixed to torque tube 28 by a pin 34 which also extends into the hub of an arm 36 mounted on the torque tube so that the arm is fixed thereto as shown in FIG. 3. Arm 36 carries a roller 38 which is contactable with a cam surface 40 arranged on mount 13 so as to be contacted by the roller during initial recoil travel of cannon 12 to convert translational displacement thereof to rotation of the arm in a counterclockwise direction. Rotation of arm 36 energizes spring 30 and, as roller 38 approaches the end of cam surface 40, a latch (not shown) secures torque tube 28 to retain the spring in the energized position.

The energy in spring 30 is used to drive breechblock 16 to the breech open position and wind spring 24, during counterrecoil travel of cannon 12 through a clutch 42, to be more fully described hereinafter. Crank 22 and arm 36 are so arranged that, when cannon 12 moves into battery and breechblock 16 into the breech closed position, roller 38 contacts cam surface 40 to stop rotation of torque tube 28 approximately 3 before crank 22 completes its stroke for a reason to be explained hereinafter.

Breechblock 16 may be operated manually by a lever 44 which is rotatingly mounted on shaft 20 outside of breech ring 14 and which is releasably connected to the shaft by a conventional latch means (not shown). To facilitate hand operation of breechblock 16, it is necessary that shaft 20 be free to rotate relative to torque tube 28 when breechblock 16 is lowered so that spring 30 will not be energized and thereby add to the manual efforts. It is also necessary, during automatic operation of cannon 12, that torque tube 28 is rotated free of shaft 20 to energize spring 30 during recoil travel of cannon 12 but is engaged with the shaft during counterrecoil travel of the cannon to transfer the energy in such spring to the shaft for moving breechblock 16 to its breech open position.

This required interrelationship of movement between shaft 20 and torque tube 28 is made possible by clutch 42 which is of sprag type. Clutch 42 includes an outer race 46 formed around the inside of shaft 20, an inner race 48 formed concentric thereto around the outside of torque tube 28, a sleeve 50 mounted for free rotation between the inner and outer races, and a plurality of sprags 52 arranged in pairs each consisting of an A sprag and a B sprag located between the inner and outer races for sprag engagement therebetween. Sleeve 50 is provided with a plurality of fingers 54 which respectively extend between the A and B sprags in each pair thereof and which are triangular in configuration and are arranged symmetrical to the radius of outer race 46 with one of the apexes directed towards the geometric center of shaft 20. A sprags are located adjacent the sides of the fingers 54 which lead, when sleeve 50 is rotated in a clockwise direction, and B sprags are adjacent the sides of the fingers which lead when the sleeve is rotated in a counterclockwise direction. A spring-biased pad 56 is mounted in breech ring 14, as shown in FIG. 3, so as to extend through a slot 57 in shaft 20 to bear frictionally against sleeve 50 to act as a drag against the free displacement thereof respective to sprags 52.

Each of the sprags 52 is provided with a semicylindrical base 58 which is rotatingly received by a matingly contoured recess in inner race 48. The recesses, which the bases 58 of B sprags, are formed directly in inner race 48 as noted at 60. The recesses, which receive bases 58 of the A sprags, are formed by a cylindrical cut 62 in inner race 48 and an insert 64 of resilient material, such as rubber, which lines such cut. Inserts 64 are designed so as to be compressed sufficiently to permit displacement of A sprags over center. A garter spring 66 biases the outer ends of the sprags 52 into contact with outer race 46 for sprag engagement therewith.

The operation of cannon 12 is as follows: Starting with breechblock 16 in the breech closed position, the parts of clutch 42 are shown in FIG. 4 wherein the A and B sprags are shown in contact with outer race 46 through the bias of garter spring 66 without interference by fingers 54. Now referring to FIG. 5, breechblock 16 is actuated to the breech open position for loading cannon 12 by latching lever 44 to shaft 20 and manually rotating the lever in a counterclockwise direction. Before shaft 20 is rotated by lever 44, A sprags are biased into contact with outer race 46 through the bias of garter spring 66. When shaft 20, and therefore outer race 46, is rotated, the resistance of torque tube 28, and therefore inner race 48, to movement, because of spring 30, the jamming force produced by rotation of the shaft by the A sprags causes inserts 64 to be compressed and thereby permit the A sprags to be pivoted over center respective to the inner and outer races and against fingers 54. Fingers 54, in turn, push against the B sprags holding them out of contact with outer race 46. During con: tinued rotation of lever 44, breechblock 16 is lowered and spring 24 is wound. When breechblock 16 reaches breech open position, it is latched therein by the extractors (not shown) according to conventional design.

A round (not shown) is then inserted into the firing tube through breech ring 14 causing the extractors (not shown) to be tripped for release of breechblock'16. Breechblock 16 is then free to be driven to the breech closed position by spring 24 which rotates shaft 20 and, therefore, crank 22 in a clockwise direction. Referring to FIG. 6, as shaft 26 is rotated, A sprigs are forced over center, permitted by the compression of inserts 64, but, because of the drag effect of pad 56 against sleeve 50, fingers 54 are held pressed against B sprags preventing displacement of the B sprags, against garter. spring 66, back into contact with outer race 46, whereby shaft 20 freewheels respective to torque tube 28 and, consequently, spring 30 is isolated from the displacement of breechblock 16 by spring 24 the weaker of the two springs.

When the chambered round is fired, cannon 12 recoils. As cannon 12 begins its recoil stroke, roller 38 contacts cam surface causing arm 36 and, therefore, torque tube 28 to rotate in a clockwise direction. Referring to FIG. 7, as torque tube 28 is rotated in a clockwise direction, A sprags are pulled over center, by compression of inserts 64, against fingers 54. Fingers 54, in turn, are pushed against B sprags which have been displaced by movement of torque tube 28. Therefore, torque tube 28 is free to be rotated respective to shaft 20 for energizing spring 30. When roller 38 reaches the end of cam surface 40, torque tube 28 is latched against counterrotation by energized spring 30 and cannon 12 continues to its full recoil length.

As cannon 12 approaches battery position during the counter recoil stroke, the latch not shown) holding torque tube 28 is automatically released according to conventional design, so that the torque tube is free to be rotated by spring 39 in the counterclockwise direction. Referring to FIG. 8, the counterclockwise rotation of torque tube 28 is transferred to shaft 20 by B sprags, which have sprag engagement therebetween, causing counterclockwise rotation of the shaft, and therefore crank 22, to drive breechblock 16 to the breech open position. Approximately 3 before crank 22 completes its rotation, roller 38 contacts cam surface 40 to stop rotation of torque tube 28 while shaft 20 continues to complete the displacement of breechblock 16 to the breech open position. This 3 rotation of shaft 20 relative to torque tube 28 is sufficient to drive A sprags over center and against fingers 54. Thus, B sprags are held out of contact with outer race 46, ready for the closing sequence of breechblock 16 as hereinbefore described. Breechblock 16 is latched in a breech open position by the extractors (not shown) as when opened manually. Another round is then inserted and the cycle is completed.

From the foregoing it is seen, because of the unique design of clutch 42, that shaft 20 is rotatable in both directions relative to torque tube 28 and that the torque tube is rotatable in one direction relative to the shaft but is engaged for transfer of torque in the other direction.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

' I claim:

1. A clutch of sprag type including a first rotary member, an outer race formed in said first rotary member, a second rotary member, an inner race formed on said second rotary member concentric to said outer race, a plurality of sprags arranged in pairs between said inner and outer races for sprag engagement therebetween so as to transfer torque from one of said rotary members to the other in both directions, a garter spring arranged for biasing said sprags into sprag engagement between said inner and outer races, and means controlling the engagement of said sprags with said outer race so that said first rotary member is rotatable relative to the second rotary member in both directions and said second rotary member is rotatable relative to said first rotary member in one direction while engaging said first rotary member to transfer a torque thereto in the other direction, said means including a resilient mounting for one of said sprags in each of said pairs thereof designed to permit displacement of said on of said sprags over center relative to said inner and outer races.

2. The clutch as defined in claim 1 and wherein said means includes a sleeve mounted between said first and second rotary members for free rotation respective thereto, a finger extending from said sleeve between said said sprags in each pair thereof, said finger being arranged to transfer displacement of said one of said sprags in the respective pair to the other one of said sprags therein so that the other one of sprags is moved out of sprag engagement between said inner and outer races, and drag means applied against said sleeve to restrain displacement thereof respective to said sprags for holding said other one of said sprags out of sprag engagement between said inner and outer races.

3. The clutch as defined in claim 1 and including recesses formed in said inner race for respectively receiving one end of each of said sprags so that the opposite end thereof is pivotal into sprag engagement with said outer race, and wherein said resilient mounting comprises an insert of compressible material arranged to line said recess for compression by said one of said sprags in each of said pairs thereof so that said one of said sprags is displaceable over center relative to said inner and outer races.

References Cited by the Examiner UNITED STATES PATENTS 4/63 Fleming 74-388 1/64 Lund 1928 

1. A CLUTCH OF SPRAG TYPE INCLUDING A FIRST ROTARY MEMBER, AN OUTER RACE FORMED IN SAID FIRST ROTARY MEMBER, A SECOND ROTARY MEMBER, AN INNER RACE FORMED ON SAID SECOND ROTARY MEMBER CONCENTRIC TO SAID OUTER RACE, A PLURALITY OF SPRAGS ARRANGED IN PAIRS BETWEEN SAID INNER AND OUTER RACES FOR SPRAG ENGAGEMENT THEREBETWEEN SO AS TO TRANSFER TORQUE FROM ONE OF SAID ROTARY MEMBERS TO THE OTHER IN BOTH DIRECTIONS, A GARTER SPRING ARRANGED FOR BIASING SAID SPRAGS INTO SPRAG ENGAGEMENT BETWEEN SAID INNER AND OUTER RACES, AND MEANS CONTROLLING THE ENGAGEMENT OF SAID SPRAGS WITH SAID OUTER RACE SO THAT SAID FIRST 